bug#62267: grep-3.9 bug: \d matches multibyte digits

[Jim Meyering]

On Sat, Mar 18, 2023 at 5:39 PM Paul Eggert <eggert@cs.ucla.edu> wrote:
> Thanks for looking into this. A couple of questions.
>
> First, some documentation issues. Why is PCRE2 incompatible with Perl on
> this issue? Are there other areas where the two are incompatible?

To be honest, I was not too concerned about keeping up with Perl
and am not worried about divergence, but admit I do not like the
implication, given the name of the option: --perl-regexp. It's always
been "pcre-regexp" in spirit. I suppose we'll want to document that,
eventually.

> Are
> these incompatibilities documented anywhere? Is the goal for 'grep -P'
> to be compatible with Perl, not with PCRE2?

Doesn't Perl have the same issue?
That's why the /a and /aa match modifiers were added.

> Second, although that patch focuses on \d, doesn't \D have a similar
> problem and shouldn't it be fixed too?

Good point about \D. Will adjust.